Dual Rod Actuator Eccentric Coupling for Friction-Free Fixation

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Solution Overview

Problem

Conventional actuator systems, such as those used in thrust reverser actuation systems, face issues with friction and additional loads due to the lack of adequate freedom of movement at fixation points, particularly the third fixation point, which can lead to 'force fighting' and damage in mechanical systems.

Innovation Solution

An eccentric coupling with a ring-shaped housing and eccentrically mounted annular disk bearings is introduced at the third fixation point to allow planar and angular movement, minimizing friction and accommodating axial thrust loads, enabling uninhibited movement of the outer rod relative to the inner rod.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional coupling structures are used to join actuator components, then the structure provides basic coupling functionality, but friction increases and freedom of movement is restricted

Engineering Contradiction:
Improvefreedom of movementVSAvoidfriction
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The coupling structure employs dynamic elements including an eccentric cam mechanism that converts rotational motion into controlled linear movement, allowing the coupling to adapt its configuration during operation. This dynamic adjustment optimizes the movement path to minimize friction while maintaining coupling integrity between actuator components.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention utilizes parameter changes through variable geometry in the coupling arms and eccentric offset distances. By varying the geometric parameters of the coupling mechanism, the system achieves optimal balance between freedom of movement and friction reduction, allowing the coupling to accommodate different movement requirements while minimizing energy loss.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If rigid coupling structures are used to prevent component movement, then stability is improved, but force fighting and damage occur due to restricted movement

Engineering Contradiction:
Improvecoupling stabilityVSAvoidcomponent durability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The coupling structure employs dynamic elements including an eccentric cam mechanism that converts rotational motion into controlled linear movement, allowing the coupling to adapt its configuration during operation. This dynamic adjustment optimizes the movement path to minimize friction while maintaining coupling integrity between actuator components.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention introduces intermediary elements in the form of bearing surfaces and lubrication channels within the coupling structure. These intermediaries facilitate smooth relative movement between coupling components, reducing direct metal-to-metal contact and preventing force fighting that would otherwise lead to component damage.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If three or more fixing points are used in actuator assemblies, then structural support is improved, but complexity increases and movement accommodation becomes difficult

Engineering Contradiction:
Improvestructural supportVSAvoidcoupling complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The coupling structure serves multiple functions simultaneously: it provides structural support at the fixing point, accommodates multi-directional movement through its articulated geometry, and acts as a friction-reducing bearing surface. This multi-functionality eliminates the need for separate components for each function, reducing overall complexity despite the presence of multiple fixing points.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The coupling is divided into segmented articulated arms connected by pivots and bearing surfaces. This segmentation allows each segment to independently accommodate movement in different directions while maintaining overall structural integrity, effectively managing the complexity of supporting multiple fixing points.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The eccentric coupling effectively reduces friction and prevents side loads on the actuator, allowing for smooth operation and reduced maintenance requirements by enabling the dual rod assembly to efficiently deploy and stow cowls and flaps with a single compact unit, reducing weight and space requirements.

Implementation Method 1

the inner and outer bearing mounts are in the form of rings or annular disks mounted within the housing for eccentric movement within the housing

Methodology Applied
Scientific EffectEccentric movement: Eccentric

Data Source

PatentEP3534038B1Actuator comprising a dual rod assembly and an eccentric coupling
Publication Date: 2023.05.03 GOODRICH ACTUATION SYST
  • EP3534038B1 patent drawingFigure 1
  • EP3534038B1 patent drawingFigure 2
  • EP3534038B1 patent drawingFigure 3A~3C

AI summary

A coupling e.g. for an actuator, comprises a housing which is preferably in the form of a ring mounted around the end of an outer rod (2) of the actuator and which can be mounted to a component e.g. a cowl being deployed. Within the housing of the coupling (7) is provided an eccentric bearing mount and bearing arrangement (100) mounted eccentrically to the housing so as to permit some eccentric movement.